For the millions of devoted fans who devoured the book on which it is based, The Help, which opened in the US this week and comes to the UK in late October, is one of the most anticipated films of 2011. It is also one of the most controversial. Directed by the little-known Tate Taylor (whose biggest credit is as an actor on indie hit Winter's Bone), the adaptation of Kathryn Stockett's bestselling novel tells the story of a young white woman, Skeeter Phelan, and her relationship with two black maids in Civil Rights-era America.

Early reviews have been largely positive and even generated some early Oscar buzz with Variety's Peter Debruge hailing its "Southern sass and feel-good sensitivity", and David Germain of Associated Press describing it as "a class act" and "popular big-screen entertainment at its best."

Even those reviewers who were less convinced, such as The Hollywood Reporter's Kurt Honeycutt, who acerbically pointed out that "the film seems as if it were made in a void of cinematic ignorance as if no motion picture of that or any other era ever tackled this topic", admitted that the acting (in particular the performances of Viola Davis and Octavia Spencer, who play the two maids) were "magnificent".

Nor was he the only one to single out the cast, with a number of US critics and bloggers predicting nominations for Davis (the stoic Aibileen), Spencer (the more defiant Minnie) and rising star Emma Stone (Skeeter) and even talk of a nod for Bryce Dallas Howard's turn as the film's villain.

On paper The Help, with its strong cast (it also features Allison Janney and Jessica Chastain), and story of triumph over adversity and friendship across the colour divide, screams Oscar-friendly fare. Hollywood loves to pat itself on the back and The Help is the sort of sentimental, broadly told and unchallenging take on race relations that you would expect to appeal to the people who named Crash best picture in 2006, and a year ago nominated The Blind Side for best film.

It helps also that it is certain to be a box-office hit: Stockett's novel, which took five years to write and was rejected by more than 45 agents, has sold more than five million copies worldwide since its publication in 2009 and, having spent 103 weeks on the New York Times bestseller list in hardback form, is currently the No 1 bestselling paperback in America. It dominates book clubs (and was chosen by Channel 4 for its TV Book Club in 2010) and was one of the two most inescapable books of last year if you happen to be a woman who reads (the other being David Nicholls's One Day). That should guarantee a huge female turnout in a post-Bridesmaids era when every Hollywood exec is searching for the next big lady-friendly film. Those same executives would have no doubt been delighted to see the New York Times's influential columnist Frank Bruni hail it as "a story of female grit and solidarity – of strength through sisterhood."

But not everyone is convinced that The Help deserves its plaudits. For while the book might be described in all the movie promotion material as "beloved", it is also controversial.

In February Ablene Cooper, a 60-year-old maid and babysitter working in Jackson, Mississippi, where The Help is set, filed a lawsuit asking for $75,000 in damages, claiming that Stockett had caused her to "experience severe emotional distress, embarrassment, humiliation and outrage" by appropriating "her identity for an unpermitted use and holding her to the public eye in a false light." Stockett denied the charges stressing that the character is fictional and "not intended to depict Mrs Cooper [whom I] met only briefly."

The case has yet to be settled but it served to shine an unwelcome spotlight on one of the biggest controversies surrounding both Stockett's novel and the upcoming film: just whose story is really being told?

Writing on the site postbourgie.com, blogger Belleisa commented on the growing category of books in which "non-black author writes really compelling story about black person (s); story gets awards, accolades, lots of press and movie deal", the implication being that, regardless of how compelling Stockett's tale might be it was her colour that allowed the book to become a mainstream hit.

Blogger Nicole Sconiers went further after viewing the film: "As trope after trope of black womanhood piled up – the sassy black woman, the noble, long-suffering black woman, the black woman dealing with an abusive man – I grew angry at Stockett, a rich, privileged white woman, for unleashing The Help on the world."

Nor is she the only one to feel that, far from being a sensitive take on race issues, The Help is as guilty of racial stereotyping as Gone With the Wind. At the detailed site acriticalreviewofthehelp.wordpress.com blogger Onyx M touched on everything from what is called the book's incorrect description of the death of Civil Rights hero Medgar Evers and its "denigration of several African American male characters" to the movie's promotional mis-steps, including questionable product tie-ins at the Home Shopping Network (including cookware and beauty products).

And at the popular Racialicious blog Latoya Peterson admitted that she was wary of both book and film, stating: "I have read stories where white authors can convincingly craft characters of colour. When they do it well, I forget who is writing. But I generally find that is not the case."

It's not the first time that a critically praised entertainment has found itself the topic of debate over its treatment of race – Mad Men has been repeatedly pulled up for its failure to either flesh out its black characters beyond walk-on roles or address Civil Rights issues in any depth – but DreamWorks, the studio behind The Help, is apparently taking no chances.

Last Friday Stone, Viola Davis and Octavia Spencer appeared on the cover of Entertainment Weekly under a strap-line saying: "How do you turn a beloved, racially charged book into a moving funny film? Very carefully". Meanwhile America's influential National Association for the Advancement of Colored People (NAACP) has swung its support behind the movie, describing it as "aligning perfectly with the values and mission of the NAACP", while hosting an advance screening in which the Civil Rights leader and former NAACP chairperson, Myrlie Evers-Williams, Medgar Evers's widow, discussed her experiences.

Davis and Spencer have also been quick to address any growing unease felt by black audiences, with Davis telling Essence magazine: "Of course I had trepidations. Why do I have to play the mammy? But what do you do as an actor if one of the most multifaceted and rich roles you've ever been given is a maid in 1962 Mississippi?"

Spencer, who is a friend of Tate Taylor and had helped perform The Help with Stockett at book readings, was more direct. "We've gotten so PC and we've gotten so weirded out," she told About.com. "We start labelling. You have to be a black person to write about black people, you have to be a white person... As a black woman, I grew up in Montgomery, Alabama and I had relatives... and a few of them had this dialect. If she wrote every black character with the exact same voice, then there would be cause for concern but she didn't do that and I think that gives it authenticity. It made me feel that I was walking in someone else's shoes... I have a problem with the fact that some people are making that an issue."

Yet perhaps the most astute comment came from the Boston Globe's film critic Wesley Morris, who wrote "one woman's mammy is another man's mother" before adding that the hardest thing to reconcile about The Help is that "on one hand it's juicy, heart-warming, well-meant entertainment. On the other, it's an owner's manual." And that, for all DreamWorks's clout and despite The NAACP's support, may yet be what prevents the film from coasting to glory come February and the Oscars.